1. Field of the Invention
This invention relates to a display device, such as an in-plane switching (IPS) type liquid crystal display device or the like device.
2. Description of the Related Art
A liquid crystal display device of the so-called in-plane switching type has been so constituted that the substrates are arranged opposed to each other with the liquid crystals sandwiched therebetween, and pixel electrodes and counter electrodes that produce an electric field relative to the pixel electrodes are formed on the pixel region of one substrate on the side of the liquid crystals, and the liquid crystals are driven by components of the electric field which are nearly in parallel with the substrate.
In the device of the active matrix type to which the above constitution is adapted, the pixel regions are formed by those regions which are surrounded by a plurality of gate signal lines arranged in parallel on the surface of one substrate on the side of the liquid crystals and by a plurality of drain signal lines arranged so as to intersect the gate signal lines.
Each pixel region is provided with a thin-film transistor that is operated by a scanning signal from a gate signal line, the pixel electrode supplied with a video signal from a drain signal line through the thin-film transistor, and the counter electrode supplied with a signal that serves as a reference to the video signal.
Here, the pixel electrode and the counter electrode are formed as striped patterns extending in their respective directions. These electrodes are usually formed in a number of two or more and are alternately arranged.
There has also been known a constitution in which counter electrodes are formed on the upper surface of an insulating film formed covering the drain signal lines, the counter electrodes being formed along the drain signal lines and having center axes thereof which are nearly in agreement with the drain signal lines and further having a width greater than the width of the drain signal lines.
This enables the lines of electric force from the drain signal lines to be terminated at the counter electrodes instead of terminating at the pixel electrodes. The lines of electric force that terminate at the pixel electrodes turn out to be noises.
In order to decrease parasitic capacitance between the drain signal lines and the counter electrodes in this constitution, the structure has been known to interpose, at least, an organic material layer such as of a resin as an interlayer insulating film between them.
It has, however, been pointed out that the liquid crystal display device which is thus constituted permits the organic material layer to be easily peeled off from the edges thereof in the step of production, the organic material layer being peeled off up to the liquid crystal display unit to cause defective display.
An inquiring of the cause revealed the following facts. That is, when the electrodes are formed on the upper surface of the organic material layer, the end surfaces of the organic material layer are exposed to a resist-developing solution, a peeling solution and to an electrode-etching solution. These liquids for the resist-developing, the peeling and the electrode-etching are for removing the residue of the organic material layer. Among them, the developing solution is used for dissolving the uncured organic material layer itself, and the peeling solution is used for removing the photoresist itself of the organic material layer after it has played its role. These liquids have a tendency of peeling the organic films off and, hence, the countermeasure must be taken based upon this as a prerequisite.